The present invention relates to cross country ski bindings of the type described in commonly assigned copending application Ser. No. 849,447, filed Nov. 7, 1977. The subject matter of said application is incorporated herein by reference thereto, to the extent desired to facilitate an understanding of the present invention.
The invention concerns a cross country ski binding with a forward retaining device, to hold the front end of the shoe sole, which can be lifted from the ski at its rear end, whereby the forward end of the sole which extends over the toe part of the shoe is hingedly connected with the ski by articulation pieces that run crosswise with reference to the ski.
Cross country ski bindings of this kind that have been proposed heretofore have a forward sole extension that extends relatively far beyond the front end of the toe part of the shoe that is formed by the upper, as in the case of so-called pointed shoes. Such bindings, with suitably adapted shoes, offer many advantages for cross country skiing, but because of the sole extension they have the drawback that normal comfortable walking is substantially hampered when the skis are taken off. The inherent loss of comfort can again offset the advantages of these bindings. Also, the bending stresses caused by the sole extension readily lead to a break unless the quality and strength of the sole sufficiently takes these stresses into account.
The invention therefore is concerned with the problem of allowing comfortable walking with the shoes that are intended for the binding when skis are removed, and of diminishing or entirely eliminating the danger of a break in the shoe sole. The invention contemplates overcoming said problems by providing that the front end of the sole--corresponding to an ordinary shoe--extends only a short distance beyond the toe part of the shoe and itself constitutes an articulation part with the axis of the articulation running directly ahead of the toe part, crosswise to the direction of the length of the ski. In particularly preferred embodiments, the front end of the sole extends less than 15 millimeters beyond the toe part of the shoe.
Because of the very small projection of the sole, which is slight even if the transverse axis of articulation is relatively far from the toe part of the shoe, there is in any case a comfortable gait when the shoes are detached from the skis. Also, the bending stresses in the shoe sole are reduced to a minimum. Since moreover the shoe sole itself is effectively part of the crosswise articulation and of the binding respectively, there is at the same time a relatively simple construction of the binding part on the ski side. For engagement of the locking member and the front end of the sole for clamping or locking it in the retaining jaw, the sole end can be of a suitable configuration and provided with a hook-like projection, a groove or the like according to various preferred embodiments of the invention.
According to a further characteristic of certain embodiments of the invention, the front end of the sole is also clamped by the locking member in the retaining jaw. The retaining jaw and/or the locking member can be urged by spring action which presses or draws them against the ski.
If the shoe sole is firmly clamped in the retaining jaw by the locking member, in that it is drawn firmly forward against its V-shaped lateral jaw parts, a secure seat for the shoe in the binding is also ensured in certain preferred embodiments. By the cooperation of the retaining jaw and the locking member on the other hand, in spite of the slight projection that corresponds to the normal sole projection, in the preferred range of a maximum of 15 mm, a lifting of the shoe about another axis of articulation at the front is possible without any constraint. The forward part of the shoe sole is clamped in preferred embodiments between the retaining jaws by means of the locking member, like a vise, whereby the locking member and the retaining jaws advantageously can mutually yield, depending upon the lift of the shoe heel or the forces acting on the shoe.
In other embodiments of the invention in which the forward end of the sole itself constitutes an articulation part of the hinge-like articulation between the shoe and ski, the sole end, to produce the necessary movability about the transverse axis, is made as at least a partly cylindrical widened body, or like a cup, to cooperate with a correspondingly bulged part which may be fixed to the ski, or in a similar or correspondingly acting way. Resilient elements, preferably pads of elastic material such as rubber, or even in some embodiments the locking member itself, which can be made as a torsion or wire spring, can serve to effect a resetting action on the shoe sole if the shoe heel lifts off the ski.
Movable binding parts such as the locking member or the retaining jaws or other elements connected with them, such as guides or the like, are preferably made at the same time as grip elements and suitably disposed so that by depression of this part the binding can be released, in that for example in certain preferred arrangements the locking member will be removed from its lock setting and thereby its engagement with the front end of the sole will be interrupted.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention.